Numerical Study on Heat Transfer Deterioration of Supercritical n-Decane in Horizontal Circular Tubes

Wang, Yanhong; Li, Sufen; Dong, Ming

doi:10.3390/en7117535

Cited by 31 publications

(6 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a typical and main component in many kinds of hydrocarbon fuel, n -decane has critical properties and pyrolytic products similar to those of the actual jet fuels commonly used in scramjet applications. , Consequently, investigations on the supercritical-pressure flow and heat transfer of n -decane have attracted wide attention over the past decades and plenty of meaningful results have been achieved. − These works were mainly devoted to the heat transfer deterioration phenomenon and provided guidance for the Nusselt number predictions under different operating conditions. In recent years, many efforts have been made by researchers to understand the pyrolysis process of n -decane under supercritical pressure.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Flow and Heat Transfer of n-Decane with Pyrolysis and Pyrolytic Coking under Supercritical Pressures

Tao

Zhu

et al. 2017

Energy Fuels

View full text Add to dashboard Cite

Pyrolysis and pyrolytic coking of hydrocarbon fuel have significant influences on the regenerative cooling process. In this article, a three-dimensional (3D) model is developed for numerically investigating the flow and heat transfer of pyrolytically reacted n-decane with pyrolytic coking in the engine cooling tube under supercritical pressure. The one-step global pyrolytic reaction mechanism and the kinetic coking model are incorporated into the numerical model to simulate the pyrolysis and pyrolytic coking process of n-decane. The numerical method is validated based on the good agreement between the current predictions and the experimental data. Numerical studies of the characteristics of pyrolysis and surface coking rate at the start time under various outer wall heat fluxes from 1.2 to 1.8 MW/m 2 have been conducted under 5 MPa. Results reveal that heat flux has huge effects on the pyrolytic reaction and the distribution of pyrolytic coking rate. In order to better understand the complicated unsteady physicochemical process, further investigations on coupling relationships between the turbulent flow, heat transfer, pyrolysis and pyrolytic coking in 20 min under a high heat flux of 1.8 MW/m 2 have been performed. It is found that surface coking brings about plenty of negative impacts on the cooling process of n-decane. The mechanisms of these physicochemical phenomena are also analyzed in detail, which would be very helpful in the development of regenerative cooling technology.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical Study of Flow and Heat Transfer of n-Decane with Pyrolysis and Pyrolytic Coking under Supercritical Pressures

Tao

Zhu

et al. 2017

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…Kurganov et al [37] discovered that the velocity profile of supercritical fuel tends to be M-shaped under heating, which decreases the turbulent kinetic energy and causes HTD [38][39][40]. Wang et al [24] and Sun et al [25] also discovered that the abnormal distributions of near-wall turbulent kinetic energy and the radial velocity or laminar-like flow are the reasons of the HTD.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Heat Transfer of n-Decane in a Horizontal Channel with Axially Nonuniform Heat Flux under Supercritical Pressure

et al. 2022

View full text Add to dashboard Cite

Regenerative cooling is considered promising in the thermal protection of hypersonic propulsion devices such as SCRamjet. However, the heat transfer deterioration (HTD) of hydrocarbon fuel is a severe threat to the thermal structure safety, especially under axially nonuniform heat flux caused by the thermal load difference in different components. In this work, the heat transfer of trans-critical n-decane in a mini-horizontal channel is numerically investigated. The influences of the axially nonuniform heat flux on the heat transfer is focused on. Two types of HTD are recognized and analyzed. The first type of HTD is induced by the near-wall flow acceleration and the local thickening of the viscous sublayer. The second type of HTD is closely related to the expansion of the low thermal conductivity λ and specific heat cp region, which is seriously worsened under axially nonuniform heat flux, especially when the heat flux peak locates where Tw ≥ Tpc. The minimum HTC deteriorates by 40.80% and the Tw_max increases from 857 K to 1071 K by 27.5%. The maximum fluctuation in pressure drop is 6.8% in the variation in heat flux distribution with Φ = 2. This work is expected to offer a reference to the proper match of fuel temperature distribution and the engine heat flux boundary in SCRamjet cooling system design.

show abstract

“…They observed heat transfer deterioration for the three kinds of light hydrocarbons at high q/G ratio. Wang et al [30] numerically studied the heat transfer of supercritical n-decane, and pointed out two kinds of heat transfer deterioration while the wall and bulk fluid temperatures were close to the pseudo-critical value.…”

Section: Introductionmentioning

confidence: 99%

Experiments on Heat Transfer of Supercritical Pressure Kerosene in Mini Tube under Ultra-High Heat Fluxes

et al. 2020

View full text Add to dashboard Cite

Heat transfer of supercritical-pressure kerosene is crucial for regenerative cooling systems in rocket engines. In this study, experiments were devoted to measure the heat transfer of supercritical-pressure kerosene under ultra-high heat fluxes. The kerosene flowed horizontally in a mini circular tube with a 1.0 mm inner diameter and was heated uniformly under pressures of 10–25 MPa, mass fluxes of 8600–51,600 kg/m2 s, and a maximum heat flux of up to 33.6 MW/m2. The effects of the operating parameters on the heat transfer of supercritical-pressure kerosene were discussed. It was observed that the heat transfer coefficient of kerosene increases at a higher mass flux and inlet bulk temperature, but is little affected by pressure. The heat transfer of supercritical-pressure kerosene is classified into two regions: normal heat transfer and enhanced heat transfer. When the wall temperature exceeds a certain value, heat transfer is enhanced, which could be attributed to pseudo boiling. This phenomenon is more likely to occur under higher heat flux and lower mass flux conditions. In addition, the experimental data were compared with several existing heat transfer correlations, in which one of these correlations can relatively well predict the heat transfer of supercritical-pressure kerosene. The results drawn from this study could be beneficial to the regenerative cooling technology for rocket engines.

show abstract

Numerical Study on Heat Transfer Deterioration of Supercritical n-Decane in Horizontal Circular Tubes

Cited by 31 publications

References 33 publications

Numerical Study of Flow and Heat Transfer of n-Decane with Pyrolysis and Pyrolytic Coking under Supercritical Pressures

Numerical Study of Flow and Heat Transfer of n-Decane with Pyrolysis and Pyrolytic Coking under Supercritical Pressures

Numerical Investigation on the Heat Transfer of n-Decane in a Horizontal Channel with Axially Nonuniform Heat Flux under Supercritical Pressure

Experiments on Heat Transfer of Supercritical Pressure Kerosene in Mini Tube under Ultra-High Heat Fluxes

Contact Info

Product

Resources

About